A cordless two-way infrared optical computer input device, which gives disabled persons access to the power of microcomputer and communications aids will be developed. Phase I identified through clinical tests that such a device is needed. The small work area restriction inherent in retroreflective head pointers is eliminated when the optical system is worn by the user. In this new configuration, a base unit transmits short pulses of infrared light towards the user. These light pulses are received by a detector unit worn by the user, which measures the user's head position and communicates it back to the basic unit. This base unit translates the data and sends it to the computer. A cursor control driver reflects head movements in cursor position on the computer screen. A keyboard image on the display enables the user to "type" with the cursor and thus operate the computer. Phase II will complete development of this system as follows: 1) set performance goals from clinical testing with disabled persons. 2) develop a cordless optical head pointer which meets the performance goals. 3) optimize cursor control and keyboard emulation software to be fully compatible with Windows and other graphics programs. 4) verify clinically the performance goals.